46 KEPORT ON THE PENNATULIDA. 



We have also investigated for the same purpose aud in the same 

 manner four specimens of Peimatula in the Owens College Museum, 

 the result being to confirm the above conclusion in all cases. 



Our account of the male Pennatuht will be found to agree very 

 closely with the description given by Kiilliker* of the male of 

 HaUsceptrum, a genus belonging to the same family as Pennatula and 

 differing from it mainly in possessing no calcareous spicules in the 

 leaves. Concerning the relative abundance of the two sexes, out of 

 six specimens of HalUcepirum examined by Kolliker five were females 

 and only one a male ; while of the six specimens of Pennatula we 

 have had an opportunity of studying, two are females and four males. 

 The close similarity, if not identity, in external form between the two 

 sexes, and also the close resemblance of the spermatospheres to the 

 ova, must make us very cautious about accepting statements concerning 

 the sexuality of specimens, unless it is explicitly stated that the 

 character of the genital products has been determined by the 

 microscope. 



5. — Anatomy of the Zookh. — 



The zooids of Pennatula, like those of Funicidina, differ from the 

 polypes in the following structural points, besides the differences in size 

 aud position alreadj- noticed : — 



1. Though there is a well-developed stomach, and as a rule a 

 mouth as well, there are no tentacles or calyx. 



2. All eight mesenteries are present around and supporting the 

 stomach, but only two of the eight have their free edges below the 

 stomach thickened to form mesenterial filaments. The two mesen- 

 terial filaments present extend down to the bottom of the body cavity 

 of the zooid, and clearly correspond to the two long slender filaments 

 of the polypes. 



3. The zooids have no reproductive organs. The walls of the 

 zooids are very thickly studded with calcareous spicules, aud the lower 

 ends of the zooid cavities communicate freely with the spongy canal 

 system of the wall of the rachis. At least two thirds of the length of 

 each zooid is embedded in the wall of the rachis, so that it is only by 

 making sections of the rachis that the anatomy of the zooids can be 

 ascertained. The smaller zooids have no mouths, and are therefore 

 dependent for their nutriment on the supply brought by the canal 

 system from the polypes. 



6. — Zoological Position and Affinities. — 



The general position of I'ennatula in the order Pennatulida is shown 

 in the table on page 1 of this report. The generic characters, as given 

 by Kolliker, t are as follows : — 



"Genus: I'ennatula — True Sea-pens, with well developed leaves, in 

 which there are no zooids and no very large calcareous rods t but a 



' Kolliker : op. cit., pp. 161-167. t Kolliker : Op. cit. p. 122. 

 ; As iu Pteroeides, e.(j. 



